/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 *****************************************************************************/

#ifndef Spine_AnimationState_h
#define Spine_AnimationState_h

#include <spine/Vector.h>
#include <spine/Pool.h>
#include <spine/MixBlend.h>
#include <spine/SpineObject.h>
#include <spine/SpineString.h>
#include <spine/HasRendererObject.h>

#ifdef SPINE_USE_STD_FUNCTION
#include <functional>
#endif

namespace spine {
	enum EventType {
		EventType_Start,
		EventType_Interrupt,
		EventType_End,
		EventType_Complete,
		EventType_Dispose,
		EventType_Event
	};

	class AnimationState;
	class TrackEntry;

	class Animation;
	class Event;
	class AnimationStateData;
	class Skeleton;
	class RotateTimeline;

#ifdef SPINE_USE_STD_FUNCTION
	typedef std::function<void (AnimationState* state, EventType type, TrackEntry* entry, Event* event)> AnimationStateListener;
#else
	typedef void (*AnimationStateListener) (AnimationState* state, EventType type, TrackEntry* entry, Event* event);
#endif

	/// Abstract class to inherit from to create a callback object
	class SP_API AnimationStateListenerObject {
	public:
		AnimationStateListenerObject() { };
		virtual ~AnimationStateListenerObject() { };
	public:
		/// The callback function to be called
		virtual void callback(AnimationState* state, EventType type, TrackEntry* entry, Event* event) = 0;
	};

	/// State for the playback of an animation
	class SP_API TrackEntry : public SpineObject, public HasRendererObject {
		friend class EventQueue;
		friend class AnimationState;

	public:
		TrackEntry();

		virtual ~TrackEntry();

		/// The index of the track where this entry is either current or queued.
		int getTrackIndex();

		/// The animation to apply for this track entry.
		Animation* getAnimation();

		/// If true, the animation will repeat. If false, it will not, instead its last frame is applied if played beyond its duration.
		bool getLoop();
		void setLoop(bool inValue);

		/// If true, when mixing from the previous animation to this animation, the previous animation is applied as normal instead
		/// of being mixed out.
		///
		/// When mixing between animations that key the same property, if a lower track also keys that property then the value will
		/// briefly dip toward the lower track value during the mix. This happens because the first animation mixes from 100% to 0%
		/// while the second animation mixes from 0% to 100%. Setting holdPrevious to true applies the first animation
		/// at 100% during the mix so the lower track value is overwritten. Such dipping does not occur on the lowest track which
		/// keys the property, only when a higher track also keys the property.
		///
		/// Snapping will occur if holdPrevious is true and this animation does not key all the same properties as the
		/// previous animation.
		bool getHoldPrevious();
		void setHoldPrevious(bool inValue);

		/// Seconds to postpone playing the animation. When a track entry is the current track entry, delay postpones incrementing
		/// the track time. When a track entry is queued, delay is the time from the start of the previous animation to when the
		/// track entry will become the current track entry.
		float getDelay();
		void setDelay(float inValue);

		/// Current time in seconds this track entry has been the current track entry. The track time determines
		/// TrackEntry.AnimationTime. The track time can be set to start the animation at a time other than 0, without affecting looping.
		float getTrackTime();
		void setTrackTime(float inValue);

		/// The track time in seconds when this animation will be removed from the track. Defaults to the animation duration for
		/// non-looping animations and to int.MaxValue for looping animations. If the track end time is reached and no
		/// other animations are queued for playback, and mixing from any previous animations is complete, properties keyed by the animation,
		/// are set to the setup pose and the track is cleared.
		///
		/// It may be desired to use AnimationState.addEmptyAnimation(int, float, float) to mix the properties back to the
		/// setup pose over time, rather than have it happen instantly.
		float getTrackEnd();
		void setTrackEnd(float inValue);

		/// Seconds when this animation starts, both initially and after looping. Defaults to 0.
		///
		/// When changing the animation start time, it often makes sense to set TrackEntry.AnimationLast to the same value to
		/// prevent timeline keys before the start time from triggering.
		float getAnimationStart();
		void setAnimationStart(float inValue);

		/// Seconds for the last frame of this animation. Non-looping animations won't play past this time. Looping animations will
		/// loop back to TrackEntry.AnimationStart at this time. Defaults to the animation duration.
		float getAnimationEnd();
		void setAnimationEnd(float inValue);

		/// The time in seconds this animation was last applied. Some timelines use this for one-time triggers. Eg, when this
		/// animation is applied, event timelines will fire all events between the animation last time (exclusive) and animation time
		/// (inclusive). Defaults to -1 to ensure triggers on frame 0 happen the first time this animation is applied.
		float getAnimationLast();
		void setAnimationLast(float inValue);

		/// Uses TrackEntry.TrackTime to compute the animation time between TrackEntry.AnimationStart. and
		/// TrackEntry.AnimationEnd. When the track time is 0, the animation time is equal to the animation start time.
		float getAnimationTime();

		/// Multiplier for the delta time when the animation state is updated, causing time for this animation to play slower or
		/// faster. Defaults to 1.
		float getTimeScale();
		void setTimeScale(float inValue);

		/// Values less than 1 mix this animation with the last skeleton pose. Defaults to 1, which overwrites the last skeleton pose with
		/// this animation.
		///
		/// Typically track 0 is used to completely pose the skeleton, then alpha can be used on higher tracks. It doesn't make sense
		/// to use alpha on track 0 if the skeleton pose is from the last frame render.
		float getAlpha();
		void setAlpha(float inValue);

		///
		/// When the mix percentage (mix time / mix duration) is less than the event threshold, event timelines for the animation
		/// being mixed out will be applied. Defaults to 0, so event timelines are not applied for an animation being mixed out.
		float getEventThreshold();
		void setEventThreshold(float inValue);

		/// When the mix percentage (mix time / mix duration) is less than the attachment threshold, attachment timelines for the
		/// animation being mixed out will be applied. Defaults to 0, so attachment timelines are not applied for an animation being
		/// mixed out.
		float getAttachmentThreshold();
		void setAttachmentThreshold(float inValue);

		/// When the mix percentage (mix time / mix duration) is less than the draw order threshold, draw order timelines for the
		/// animation being mixed out will be applied. Defaults to 0, so draw order timelines are not applied for an animation being
		/// mixed out.
		float getDrawOrderThreshold();
		void setDrawOrderThreshold(float inValue);

		/// The animation queued to start after this animation, or NULL.
		TrackEntry* getNext();

		/// Returns true if at least one loop has been completed.
		bool isComplete();

		/// Seconds from 0 to the mix duration when mixing from the previous animation to this animation. May be slightly more than
		/// TrackEntry.MixDuration when the mix is complete.
		float getMixTime();
		void setMixTime(float inValue);

		/// Seconds for mixing from the previous animation to this animation. Defaults to the value provided by
		/// AnimationStateData based on the animation before this animation (if any).
		///
		/// The mix duration can be set manually rather than use the value from AnimationStateData.GetMix.
		/// In that case, the mixDuration must be set before AnimationState.update(float) is next called.
		///
		/// When using AnimationState::addAnimation(int, Animation, bool, float) with a delay
		/// less than or equal to 0, note the Delay is set using the mix duration from the AnimationStateData
		float getMixDuration();
		void setMixDuration(float inValue);

		MixBlend getMixBlend();
		void setMixBlend(MixBlend blend);

		/// The track entry for the previous animation when mixing from the previous animation to this animation, or NULL if no
		/// mixing is currently occuring. When mixing from multiple animations, MixingFrom makes up a double linked list with MixingTo.
		TrackEntry* getMixingFrom();

		/// The track entry for the next animation when mixing from this animation, or NULL if no mixing is currently occuring.
		/// When mixing from multiple animations, MixingTo makes up a double linked list with MixingFrom.
		TrackEntry* getMixingTo();

		/// Resets the rotation directions for mixing this entry's rotate timelines. This can be useful to avoid bones rotating the
		/// long way around when using alpha and starting animations on other tracks.
		///
		/// Mixing involves finding a rotation between two others, which has two possible solutions: the short way or the long way around.
		/// The two rotations likely change over time, so which direction is the short or long way also changes.
		/// If the short way was always chosen, bones would flip to the other side when that direction became the long way.
		/// TrackEntry chooses the short way the first time it is applied and remembers that direction.
		void resetRotationDirections();

		void setListener(AnimationStateListener listener);

		void setListener(AnimationStateListenerObject* listener);

	private:
		Animation* _animation;

		TrackEntry* _next;
		TrackEntry* _mixingFrom;
		TrackEntry* _mixingTo;
		int _trackIndex;

		bool _loop, _holdPrevious;
		float _eventThreshold, _attachmentThreshold, _drawOrderThreshold;
		float _animationStart, _animationEnd, _animationLast, _nextAnimationLast;
		float _delay, _trackTime, _trackLast, _nextTrackLast, _trackEnd, _timeScale;
		float _alpha, _mixTime, _mixDuration, _interruptAlpha, _totalAlpha;
		MixBlend _mixBlend;
		Vector<int> _timelineMode;
		Vector<TrackEntry*> _timelineHoldMix;
		Vector<float> _timelinesRotation;
		AnimationStateListener _listener;
		AnimationStateListenerObject* _listenerObject;

		void reset();
	};

	class SP_API EventQueueEntry : public SpineObject {
		friend class EventQueue;

	public:
		EventType _type;
		TrackEntry* _entry;
		Event* _event;

		EventQueueEntry(EventType eventType, TrackEntry* trackEntry, Event* event = NULL);
	};

	class SP_API EventQueue : public SpineObject {
		friend class AnimationState;

	private:
		Vector<EventQueueEntry> _eventQueueEntries;
		AnimationState& _state;
		Pool<TrackEntry>& _trackEntryPool;
		bool _drainDisabled;

		static EventQueue* newEventQueue(AnimationState& state, Pool<TrackEntry>& trackEntryPool);

		static EventQueueEntry newEventQueueEntry(EventType eventType, TrackEntry* entry, Event* event = NULL);

		EventQueue(AnimationState& state, Pool<TrackEntry>& trackEntryPool);

		~EventQueue();

		void start(TrackEntry* entry);

		void interrupt(TrackEntry* entry);

		void end(TrackEntry* entry);

		void dispose(TrackEntry* entry);

		void complete(TrackEntry* entry);

		void event(TrackEntry* entry, Event* event);

		/// Raises all events in the queue and drains the queue.
		void drain();
	};

	class SP_API AnimationState : public SpineObject, public HasRendererObject {
		friend class TrackEntry;
		friend class EventQueue;

	public:
		explicit AnimationState(AnimationStateData* data);

		~AnimationState();

		/// Increments the track entry times, setting queued animations as current if needed
		/// @param delta delta time
		void update(float delta);

		/// Poses the skeleton using the track entry animations. There are no side effects other than invoking listeners, so the
		/// animation state can be applied to multiple skeletons to pose them identically.
		bool apply(Skeleton& skeleton);

		/// Removes all animations from all tracks, leaving skeletons in their previous pose.
		/// It may be desired to use AnimationState.setEmptyAnimations(float) to mix the skeletons back to the setup pose,
		/// rather than leaving them in their previous pose.
		void clearTracks();

		/// Removes all animations from the tracks, leaving skeletons in their previous pose.
		/// It may be desired to use AnimationState.setEmptyAnimations(float) to mix the skeletons back to the setup pose,
		/// rather than leaving them in their previous pose.
		void clearTrack(size_t trackIndex);

		/// Sets an animation by name. setAnimation(int, Animation, bool)
		TrackEntry* setAnimation(size_t trackIndex, const String& animationName, bool loop);

		/// Sets the current animation for a track, discarding any queued animations.
		/// @param loop If true, the animation will repeat.
		/// If false, it will not, instead its last frame is applied if played beyond its duration.
		/// In either case TrackEntry.TrackEnd determines when the track is cleared.
		/// @return
		/// A track entry to allow further customization of animation playback. References to the track entry must not be kept
		/// after AnimationState.Dispose.
		TrackEntry* setAnimation(size_t trackIndex, Animation* animation, bool loop);

		/// Queues an animation by name.
		/// addAnimation(int, Animation, bool, float)
		TrackEntry* addAnimation(size_t trackIndex, const String& animationName, bool loop, float delay);

		/// Adds an animation to be played delay seconds after the current or last queued animation
		/// for a track. If the track is empty, it is equivalent to calling setAnimation.
		/// @param delay
		/// Seconds to begin this animation after the start of the previous animation. May be &lt;= 0 to use the animation
		/// duration of the previous track minus any mix duration plus the negative delay.
		///
		/// @return A track entry to allow further customization of animation playback. References to the track entry must not be kept
		/// after AnimationState.Dispose
		TrackEntry* addAnimation(size_t trackIndex, Animation* animation, bool loop, float delay);

		/// Sets an empty animation for a track, discarding any queued animations, and mixes to it over the specified mix duration.
		TrackEntry* setEmptyAnimation(size_t trackIndex, float mixDuration);

		/// Adds an empty animation to be played after the current or last queued animation for a track, and mixes to it over the
		/// specified mix duration.
		/// @return
		/// A track entry to allow further customization of animation playback. References to the track entry must not be kept after AnimationState.Dispose.
		///
		/// @param trackIndex Track number.
		/// @param mixDuration Mix duration.
		/// @param delay Seconds to begin this animation after the start of the previous animation. May be &lt;= 0 to use the animation
		/// duration of the previous track minus any mix duration plus the negative delay.
		TrackEntry* addEmptyAnimation(size_t trackIndex, float mixDuration, float delay);

		/// Sets an empty animation for every track, discarding any queued animations, and mixes to it over the specified mix duration.
		void setEmptyAnimations(float mixDuration);

		/// @return The track entry for the animation currently playing on the track, or NULL if no animation is currently playing.
		TrackEntry* getCurrent(size_t trackIndex);

		AnimationStateData* getData();

		/// A list of tracks that have animations, which may contain NULLs.
		Vector<TrackEntry*> &getTracks();

		float getTimeScale();
		void setTimeScale(float inValue);

		void setListener(AnimationStateListener listener);
		void setListener(AnimationStateListenerObject* listener);

		void disableQueue();
		void enableQueue();

	private:

		AnimationStateData* _data;

		Pool<TrackEntry> _trackEntryPool;
		Vector<TrackEntry*> _tracks;
		Vector<Event*> _events;
		EventQueue* _queue;

		HashMap<int, bool> _propertyIDs;
		bool _animationsChanged;

		AnimationStateListener _listener;
		AnimationStateListenerObject* _listenerObject;

		float _timeScale;

		static Animation* getEmptyAnimation();

		static void applyRotateTimeline(RotateTimeline* rotateTimeline, Skeleton& skeleton, float time, float alpha, MixBlend pose, Vector<float>& timelinesRotation, size_t i, bool firstFrame);

		/// Returns true when all mixing from entries are complete.
		bool updateMixingFrom(TrackEntry* to, float delta);

		float applyMixingFrom(TrackEntry* to, Skeleton& skeleton, MixBlend currentPose);

		void queueEvents(TrackEntry* entry, float animationTime);

		/// Sets the active TrackEntry for a given track number.
		void setCurrent(size_t index, TrackEntry *current, bool interrupt);

		TrackEntry* expandToIndex(size_t index);

		/// Object-pooling version of new TrackEntry. Obtain an unused TrackEntry from the pool and clear/initialize its values.
		/// @param last May be NULL.
		TrackEntry* newTrackEntry(size_t trackIndex, Animation *animation, bool loop, TrackEntry *last);

		/// Dispose all track entries queued after the given TrackEntry.
		void disposeNext(TrackEntry* entry);

		void animationsChanged();

		void computeHold(TrackEntry *entry);

		void computeNotLast(TrackEntry *entry);
	};
}

#endif /* Spine_AnimationState_h */